common: Drop display_options.h from common header

Move this out of the common header and include it only where needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/net/nfs.c b/net/nfs.c
index 9f65cfb20..c6a1248 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -28,6 +28,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <display_options.h>
 #ifdef CONFIG_SYS_DIRECT_FLASH_NFS
 #include <flash.h>
 #endif